<!DOCTYPE html>
<html>
  <head>
  </head>
  <body>
    <div id="container"><div id="host"></div></div>
    <script>
      var host = document.getElementById("host");
      var root = host.createShadowRoot();
      root.innerHTML = 'inside shadow DOM';

      var container = document.getElementById("container");
      container.removeChild(host);
      container.appendChild(host);
    </script>
  </body>
</html>